Clock controlled receiver



2 Sheets-Sheet 1 Filed Feb. 18, 1959 INVENTOR.

GEORGE w R QEE E31 \w ME Q \m mskhnfim SSE NM QNERQQ mu m QEQEE nrratwiyMarch 20, 1962 G. L. BEERS CLOCK CONTROLLED RECEIVER Filed Feb. 18, 1959FUD/0 007/ 07 I746! 2 Sheets-Sheet 2 .lllll INVENTOR. EEIJREE L. BEERSUnited States Patent 3,026,411 CLOCK CONTROLLED RECEIVER George L.Beers, Haddonfield, N.J., assignor to Radio Corporation of America, acorporation of Delaware Filed Feb. 18, 1959, Ser. No. 794,188 2 Claims.(Cl. 250-20) This invention relates to radio receivers of the type whichare adapted to be energized at a predetermined time by a clockcontrolled switch to produce an audible alarm.

Certain types of clock controlled receivers heretofore known haveprovided the option of a radio program type alarm or a buzzer typealarm. With the radio program type alarm the receiver is energized at apreset time to receive and translate a preselected radio program. Withthe buzzer alarm, a conventional alarm device usually an electricallyoperated buzzer associated with the clock mechanism is energized at thepreset time to produce an audible time or buzz. v

It is an object of this invention to provide an improved and simplifiedclock controlled receiver which provides the option of a radio programtype alarm or a tone alarm of a more pleasing character thanconventional electromechanical buzzer alarms yet effective to awaken asleeping person.

Another object of this invention is to provide an improved clockreceiver of the type including a tone alarm which does not require theaddition of a separate alarm device ordinarily associated with the clockmechanism.

A further object of this invention. is to provide an improved clockreceiver of the type including a tone alarm wherein greater flexibilityis provided in selecting such qualities of the resulting alarm tone asfrequency or volume.

The clock controlled receiver of the present invention includesfunctionselector control means for optionally selecting the radioprogram type or tone type alarm. In the radio program type alarmposition of the function selector control means, power is supplied tothe receiver at a preset time by a clock controlled switch so that areceived broadcast signal may be reproduced in the usual manner. In thetone type alarm position of the function selector control means, theoutput circuit of the audio power amplifier is regeneratively coupled toa preceding point in the signal channel in a manner to produceoscillations, so that when the receiver is energized at the preset time,an audible tone is produced by the receiver loadspeaker. In this mannerthe buzzer type alarm can be provided on a clock controlled receiverwithout requiring the additional expense and space required by aconventional alarm device. Furthermore, a greater degree of flexibilityis provided for controlling the qualities of the alarm tone in that thefrequency and volume can be more readily controlled by the properselection or adjustment of the circuit elements.

The novel features that are considered characteristic of this inventionare set forth in the appended claims. The invention itself, however,both as to its organization and method of operation, as well asadditional objects and advantages thereof, will best be understood fromthe following description when read in connection with the accompanyingdrawings, in which:

FIGURE 1 is a schematic circuit diagram of a clock controlled radioreceiver embodying the invention;

FIGURE 2 is a diagrammatic representation of a practical functionselector control switch. for the receiver shown in FIG. 1; and

FIGURE 3 is a modification of the loudspeaker circuit of FIGURE 1, forproviding a diiferent buzzer tone and selective control of the buzzervolume. V

The receiver circuit of FIGURE 1 includes a pentagrid converter 10, anintermediate frequency (I.F.) amplifier 12, a detector and audioamplifier 14 and an audio power amplifier 16 for driving a loudspeaker18. Energizing potentials for the various signal translating stages ofthe receiver are provided by a power supply 20 which comprisesconventional means for supplying a direct voltage such as a battery or arectifier circuit adapted to be connected to an AC. power main or thelike. The aforementioned circuits are of conventional design and furtherdescription of them or their operation so far as the reception andtranslation of radio signals are concerned is deemed unnecessary.

The receiver includes a function selector control means 22 which ismechanically coupled to the switch sections 24 and 26. The functioncontrol means is adjustable to: (1) turn the receiver off; (2) turn thereceiver on; (3) set the receiver for radio alarm; or (4) set thereceiver for tone alarm. As shown in the drawings, the switches 24 and26 are in the receiver on position.

The switch 24 is in the power circuits of the receiver and the switch 26is connected in the signal conveying circuits. To turn the receiver off,the movable contacts 24a and 26a of these switches are moved to engagethe open contacts 24b and 26b respectively. In this position of theswitch 24 the power supply circuit is open and the receiver isdeenergized.

To turn the receiver on, the movable contacts 24a and 26a of theswitches are moved to engage the contacts 240 and 260 respectively. Thiscauses an energizing voltage to be applied to the various signaltranslating stages, and connects the receiver to translate receivedbroadcast signals.

The B+ operating current path for the receiver may be traced from thepositive terminalv 28 of the power supply 20 through the anode tocathode paths of the various signal translating stages back to thereceiver ground line 32. From the ground line 32 the 13+. current flowsthrough a conductor 34, switch 24 and a conductor 36 back to thenegative terminal 38 of the power supply 20.

The signal path in this position of the function control means 22 isfrom the tap 40 on a conventional volume control potentiometer 42through the switch 26 and a capacitor 44 to the control electrode of theaudio amplifier portion of the stage 14.

When the function selector control means 22 is set to the radio alarmposition, the movable contacts 24a and 26a are connected to the fixedcontacts 24d and 26d respectively. The signal path for this setting isexactly the same as described above for the receiver on position. Thepower supply circuits,however, are completed from the switch 24 througha conductor 46 and a clock controlled switch 48, back to the negativeterminal 38 of the power supply 20.

The electric clock is schematically represented by the winding 50, theterminals of which are connected across the power supply terminals 28,38. As is conventional with clock controlled receivers, the clock may beset to close the contacts of the switch 48 at a predeterminedtimeusually up to about 12 hours in advance. After the clock alarm time hasbeen set and the function control selector switch has been adjusted tothe radio alarm position, the receiver will remain deenergized until thepreset time. At the preset time, the clock mechanism causes the contactsof the switch 48 to close, thereby energizing the receiver to translatesignals broadcast on a carrier frequency to which the receiver is tuned.

In the tone alarm position of the function selector switch 22, themovable contacts 24a and 26a are connected with the fixed contacts 24cand 262, respectively. Since the fixed contacts 24d and 24s areconnected together, the power circuits are completed in the same mannoras described for the radio-alarm position of the function selectorswitch. However, the control grid of the audio amplifier portion of thestage 14 is disconnected from the volume control potentiometer 42 andthereby the preceding stages of the receiver, and is regenerativelycoupled to the secondary winding of the output transformer 52.

One side of the output transformer secondary winding and the speakerwinding is indicated as being connected to the conductive chassis of thereceiver but could as vwell be connected to the ground line 32 ifdesired. The other side of this secondary winding is connected through acapacitor 54 and a resistor 56 to the ground line 32.. The junction ofthe resistor'56 and capacitor 54 is connected through a switch 58 andthe switch 26 to the grid of the audio amplifier portion of the stage14. The feedback through this network is regenerative, and causes theaudio amplifier portion of the receiver to oscillate, and thereby causesthe loudspeaker it; to produce an audible tone of pleasing quality. Thefrequency of the alarm tone can be controlled by proper design of thefeedback circuit using conventional design techniques. For example, witha feedback circuit including the resistors 6t), 62 and 64, as shown inFIGURE 3, the frequency of the alarm tone can be lowered.

As is also shown in FIGURE 3, control of the alarm tone volume may beefiected by the addition of a switch 66 and a variable resistor 68. Theswitch 66 and variable resistor 68 are connected in parallel between thelow signal potential side of the speaker winding, and the conductivechassis; The switch 66 is preferably ganged with the switches 24 and 26for control by the function setector control means 22, so that thecontacts thereof are opened only in the buzzer alarmposition of functionselector control means. With the contacts of the switch 66 open, thevariable resistor 68 is connected in series with the speaker winding,and can be adjusted to control the amount of energy delivered thereto.This, of course,

' determines the volume or loudness of the tone alarm emanating from thespeaker. In all other positions of the function selector control means22, the variable. resistor 68 is shorted out by the switch 66.

Another feature of the invention is that an interrupted tone isproducedto provide a more effective alarm sig nal. Referring again toFIGURE 1, the switch 58 in the regenerative feedback is adapted to beperiodically opened by a cam 70 on the clock mechanism. Of course othermeans such as a blocking oscillator may be used to produce theinterrupted tone. If desired, the switch 58 and the cam 70 may beeliminated to simplify the clock mechanism and to reduce the cost of thereceiver.

A practical embodiment of the switches 24 and 26 is shown in FIGURE 2.This switch is of the type commonly referred to as a wafer switch, andincludes an insulating support having fixed contacts disposed in spacedrelation about the periphery thereof. The fixed contacts 24b, 24c, 24a,24a, 26b, 260, 26a and 26e respectively correspond to the contactsbearing the same reference numerals on the switches 24 and 26 of FIGURE1, and the contacts 24 and 26f correspond to the unnumbered pivotcontacts for the movable contacts 24a and 26a re spectively of FIGURE 1.

The various contacts are positioned to cooperate with a pair ofconductive rotor elements 24a and 26a respectively. The rotor elementsare mounted for rotation by the function selector control means, whichis notshown in FIGURE 2. Suitable detent and stop means, not shown, maybe associated with the rotor elements to provide a positive stop at eachof the function selecting positions, and. to provide the desired numbero-fsuch positions.

' It will be noted that the fixed contacts 24) and 26f are longer thanthe other contacts, and are incontactwith the rotors 24a and 26arespectively for all positions thereof. The-rotors 24a and Z6 areprovided with radially extending tabs which engage one or another of theshorter fixed contacts depending on the position of the functionselector control means. In the position shown, the switch is in thereceiver olf position, and for successive counter-clockwise positionsthe switch is in the receiver on position, radio alarm position, andtone alarm position.

In accordance with the foregoing it will be seen that the clockcontrolled receiver of the invention provides the advantages of a buzzeror tone type alarm using circuits already incorporated in the receiver,and thereby eliminating the expense of a separate alarm deviceassociated with the clock mechanism. Furthermore, in addition toenabling a greater degree of flexibility with respect to the tonequality and volume of the tone alarm, a tone type alarm in accordancewith the present invention requires less power than electricallyoperated alarm devices ordinarily associated with electric clockmechanism. This is of particular importance where the receiver is to bebattery operated.

Having described my invention what is claimed is:

1. In a clock controlled radio receiver of the type including meansproviding signal translating stages for deriving audio signalinformation from received audio signal modulated carrier waves, an audiofrequency amplifier stage having an input circuit and an output circuit,a sound reproducing means coupled to said output circuit, meansproviding an energizing power source for said receiver, an electricclock connected to receive power from said source, a switch coupled tothe mechanism of said clock to be actuated from an open condition to aclosed condition at a predetermined time, circuit means including saidswitch for applying said power from said source to said signaltranslating stages and said audio frequency amplifier stage when saidswitch is in the closed condition thereof and for breaking the circuitfrom said source to said signal translating stages and said audiofrequency amplifier when the switch is in the open condition thereof;the combination of a variable resistor and function selector controlmeans having a first position for connecting said audio amplifier tosaid signal translating stages to apply audio signal information fromsaid signal translating stages to said audio amplifier input circuit' toprovide a radio alarm when said switch is in the closed conditionthereof, and a second position for connecting the output circuit of saidaudio amplifier with the input circuit thereof in regenerative relationto cause said audio amplifier to oscillate and provide a tone alarm whensaid switch is in the closed condition thereof and for con necting saidvariable resistor in circuit with said sound reproducing means toprovide an adjustable control of the volume of the tone alarm.

2. A clock controlled radio receiver comprising means providing signaltranslating stages for deriving audio signal information from receivedaudio signal modulated carrier waves, an audio frequency amplifier stagehaving an input circuit and an output circuit, a sound reproducing meanscoupled to said output circuit, means providing amplifier stage whensaid switch is in the closed condi-. tion thereof and for breaking thecircuit from said source to said signal translating stages and saidaudio frequency amplifier when the switch is in the open conditionthereof, a resistance capacitance network, a second switch, a camoperated by said clock for periodically opening said switch, functionselector control means having a first posi-.. tion for connecting saidaudio amplifierto said signal translating stages to apply audio signalinformation from said signal translating stages to said audio amplifierinput circuit to provide a radio alarm when said switch is in the closedcondition thereof and a second position for connecting said resistancecapacitance network and said second switch in series between the outputcircuit of said audio amplifier with the input circuit thereof inregenerative relation to cause said audio amplifier to oscillate andproduce an interrupted tone alarm when said switch is in the closedcondition thereof, a variable resistor, and a third switch actuated bythe function selector control means in the second position thereof toconnect said variable resistor in circuit with said sound reproducingmeans to provide anadjustable control of the tone alarm volume.

UNITED STATES PATENTS Kent Mar. 17, Hull Dec. 8, Appel Oct. 31, BeersJan. 16, Brittain Aug. 17, Selinger Nov. 22, Crane Mar. 7, Southard Aug.12, Kuhl et al. Apr. 14,

FOREIGN PATENTS Great Britain Sept. 24,

Switzerland Jan. 3,

